package com.smec.moblie.widget;

import android.content.Context;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.TranslateAnimation;
import android.widget.ScrollView;

/**
 * Created by sunxinwei on 16/2/2.
 */
public class MainDetailScrollView extends ScrollView {
    private View inner;// 孩子

    private float y;// 坐标

    private Rect normal = new Rect();// 矩形空白

    public MainDetailScrollView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }


    @Override
    protected void onFinishInflate() {
        if (getChildCount() > 0) {
            inner = getChildAt(0);// 获取其孩子
        }
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        if (inner != null) {
            commOnTouchEvent(ev);
        }
        return super.onTouchEvent(ev);
    }


    public void commOnTouchEvent(MotionEvent ev) {
        int action = ev.getAction();
        switch (action) {
            case MotionEvent.ACTION_DOWN:
                y = ev.getY();// 获取点击y坐标
                break;
            case MotionEvent.ACTION_UP:
                if (isNeedAnimation()) {
                    animation();
                }
                break;
            case MotionEvent.ACTION_MOVE:
                final float preY = y;
                float nowY = ev.getY();
                int deltaY = (int) (preY - nowY);// 获取滑动距离

                y = nowY;
                // 当滚动到最上或者最下时就不会再滚动，这时移动布局
                if (isNeedMove()) {
                    if (normal.isEmpty()) {
                        // 填充矩形，目的：就是告诉this:我现在已经有了，你松开的时候记得要执行回归动画.
                        normal.set(inner.getLeft(), inner.getTop(),
                                inner.getRight(), inner.getBottom());
                    }
                    // 移动布局
                    inner.layout(inner.getLeft(), inner.getTop() - deltaY / 2,
                            inner.getRight(), inner.getBottom() - deltaY / 2);
                }
                break;

            default:
                break;
        }
    }


    public void animation() {
        // 开启移动动画
        TranslateAnimation ta = new TranslateAnimation(0, 0, inner.getTop(),
                normal.top);
        ta.setDuration(200);
        inner.startAnimation(ta);
        // 设置回到正常的布局位置
        inner.layout(normal.left, normal.top, normal.right, normal.bottom);
        normal.setEmpty();// 清空矩形

    }


    public boolean isNeedAnimation() {
        return !normal.isEmpty();
    }


    public boolean isNeedMove() {
        int offset = inner.getMeasuredHeight() - getHeight();
        int scrollY = getScrollY();
        // 0是顶部，后面那个是底部
        if (scrollY == 0 || scrollY == offset) {
            return true;
        }
        return false;
    }

}
